RFR(XS): JDK-8040921: Uninitialised memory in hotspot/src/share/vm/c1/c1_LinearScan.cpp

[Morris Meyer]

Vladimir,

I found that you cannot move the variables and initialization down to 
the use, as the cpu_lsw.walk() // IntervalWalker.walk_to() code changes 
the intervals and causes an assertion failure in LinearScan::is_sorted().

I've commented the code to note that the code cannot be moved down to 
where it is used.

Thanks,

--morris

WEBREV - http://cr.openjdk.java.net/~morris/JDK-8040921.08
BUG - https://bugs.openjdk.java.net/browse/JDK-8040921


On 7/22/14, 6:40 PM, Vladimir Kozlov wrote:
> You did not do for fpu registers what Christian said:
>
> "We should move the variables and initialization down to the use"
>
> Vladimir
>
> On 7/22/14 12:46 PM, Morris Meyer wrote:
>> Folks,
>>
>> Could I get a review of this parfait issue. It has been tested through
>> JPRT.
>>
>> Thanks!
>>
>> --morris
>>
>> JBS - http://bugs.openjdk.java.net/browse/JDK-8040921
>> WEBREV - http://cr.openjdk.java.net/~morris/JDK-8040921.07
>>
>> On 5/1/14, 9:51 PM, Christian Thalinger wrote:
>>>
>>> On May 1, 2014, at 8:34 AM, Morris Meyer <morris.meyer at oracle.com
>>> <mailto:morris.meyer at oracle.com>> wrote:
>>>
>>>> The parfait error is with the ASSERT define blocking out
>>>> initialization of a the fpu structures when that code path is enabled.
>>>>
>>>> I've removed the ifdef such that both paths initialized their cpu and
>>>> fpu variables, and the assertion is always checked.
>>>
>>> But the code path using the uninitialized variables is also under:
>>>
>>> 1648 if (has_fpu_registers()) {
>>>
>>> Am I missing something? Anyway, during an earlier internal review I
>>> said we should keep the assert; I take that back. We should move the
>>> variables and initialization down to the use and remove the assert.
>>> It doesn’t have much value anyway.
>>>
>>>>
>>>> --mm
>>>>
>>>> On 4/30/14, 3:36 PM, Christian Thalinger wrote:
>>>>> I don’t understand the Parfait error here. Could you explain?
>>>>>
>>>>> On Apr 30, 2014, at 7:40 AM, Morris Meyer <morris.meyer at oracle.com
>>>>> <mailto:morris.meyer at oracle.com>> wrote:
>>>>>
>>>>>> Folks,
>>>>>>
>>>>>> Could I get a review for this Parfait uninitialized variable issue?
>>>>>> This has been tested with JPRT and a clear pass with Parfait.
>>>>>>
>>>>>> Thanks,
>>>>>>
>>>>>> --mm
>>>>>>
>>>>>> BUG - https://bugs.openjdk.java.net/browse/JDK-8040921
>>>>>> WEBREV - http://cr.openjdk.java.net/~morris/JDK-8040921.05
>>>>>> <http://cr.openjdk.java.net/%7Emorris/JDK-8040921.05>
>>>>>>
>>>>>>
>>>>
>>>
>>